CoreWebView2Environment.CreateWebFileSystemFileHandle Method

Definition

Namespace:

Microsoft.Web.WebView2.Core

Assembly:

Microsoft.Web.WebView2.Core.dll

Package:

Microsoft.Web.WebView2 v1.0.2849.39

Create a ICoreWebView2FileSystemHandle object from a path that represents a Web FileSystemFileHandle.

        The `path` is the path pointed by the file and must be a syntactically correct fully qualified
        path, but it is not checked here whether it currently points to a file. If an invalid path is
        passed, an E_INVALIDARG will be returned and the object will fail to create. Any other state
        validation will be done when this handle is accessed from web content
        and will cause the DOM exceptions described in
        [FileSystemFileHandle methods](https://developer.mozilla.org/docs/Web/API/FileSystemDirectoryHandle#instance_methods)
        if access operations fail.

        `Permission` property is used to specify whether the Handle should be created with a Read-only or
        Read-and-write web permission. For the `permission` value specified here, the DOM
        [PermissionStatus](https://developer.mozilla.org/docs/Web/API/PermissionStatus) property
        will be [granted](https://developer.mozilla.org/docs/Web/API/PermissionStatus/state)
        and the unspecified permission will be
        [prompt](https://developer.mozilla.org/docs/Web/API/PermissionStatus/state). Therefore,
        the web content then does not need to call
        [requestPermission](https://developer.mozilla.org/docs/Web/API/FileSystemHandle/requestPermission)
        for the permission that was specified before attempting the permitted operation,
        but if it does, the promise will immediately be resolved
        with 'granted' PermissionStatus without firing the WebView2
        [PermissionRequested](/microsoft-edge/webview2/reference/win32/icorewebview2permissionrequestedeventargs)
        event or prompting the user for permission. Otherwise, `requestPermission` will behave as the
        status of permission is currently `prompt`, which means the `PermissionRequested` event will fire
        or the user will be prompted.
        Additionally, the app must have the same OS permissions that have propagated to the
        [WebView2 browser process](/microsoft-edge/webview2/concepts/process-model)
        for the path it wishes to give the web content to read/write the file.
        Specifically, the WebView2 browser process will run in same user, package identity, and app
        container of the app, but other means such as security context impersonations do not get
        propagated, so such permissions that the app has, will not be effective in WebView2.
        Note: An exception to this is, if there is a parent directory handle that
        has broader permissions in the same page context than specified in here, the handle will automatically
        inherit the most permissive permission of the parent handle when posted to that page context.
        i.e. If there is already a `FileSystemDirectoryHandle` to `C:\example` that has write permission on
        a page, even though a WebFileSystemHandle to file `C:\example\file.txt` is created with
        `COREWEBVIEW2_FILE_SYSTEM_HANDLE_PERMISSION_READ_ONLY` permission, when posted to that page, write permission
        will be automatically granted to the created handle.

        An app needs to be mindful that this object, when posted to the web content, provides it with unusual
        access to OS file system via the Web FileSystem API! The app should therefore only post objects
        for paths that it wants to allow access to the web content and it is not recommended that the web content
        "asks" for this path. The app should also check the source property of the target to ensure
        that it is sending to the web content of intended origin.

        Once the object is passed to web content, if the content is attempting a read,
        the file must be existing and available to read similar to a file chosen by
        [open file picker](https://developer.mozilla.org/docs/Web/API/Window/showOpenFilePicker),
        otherwise the read operation will
        [throw a DOM exception](https://developer.mozilla.org/docs/Web/API/FileSystemFileHandle/getFile#exceptions).
        For write operations, the file does not need to exist as `FileSystemFileHandle` will behave
        as a file path chosen by
        [save file picker](https://developer.mozilla.org/docs/Web/API/Window/showSaveFilePicker)
        and will create or overwrite the file, but the parent directory structure pointed
        by the file must exist and an existing file must be available to write and delete
        or the write operation will
        [throw a DOM exception](https://developer.mozilla.org/docs/Web/API/FileSystemFileHandle/createWritable#exceptions).

public Microsoft.Web.WebView2.Core.CoreWebView2FileSystemHandle CreateWebFileSystemFileHandle (string Path, Microsoft.Web.WebView2.Core.CoreWebView2FileSystemHandlePermission Permission);

member this.CreateWebFileSystemFileHandle : string * Microsoft.Web.WebView2.Core.CoreWebView2FileSystemHandlePermission -> Microsoft.Web.WebView2.Core.CoreWebView2FileSystemHandle

Public Function CreateWebFileSystemFileHandle (Path As String, Permission As CoreWebView2FileSystemHandlePermission) As CoreWebView2FileSystemHandle

Parameters

Path

String

The path pointed by the file. This must be a syntactically correct fully qualified path, but it is not checked here whether it currently points to a file. If an invalid path is passed, an InvalidArgumentException will be thrown. Any other state validation will be done when this handle is accessed from web content and will cause the DOM exceptions described in FileSystemFileHandle methods if access operations fail

Permission

CoreWebView2FileSystemHandlePermission

This is used to specify whether the Handle should be created with a Read-only or Read-and-write web permission. For the permission value specified here, the DOM PermissionStatus property will be [granted](https://developer.mozilla.org/docs/Web/API/PermissionStatus/state) and the unspecified permission will be [prompt](https://developer.mozilla.org/docs/Web/API/PermissionStatus/state). Therefore, the web content then does not need to call requestPermission for the permission that was specified before attempting the permitted operation, but if it does, the promise will immediately be resolved with 'granted' PermissionStatus without firing the PermissionRequested event or prompting the user for permission. Otherwise, requestPermission will behave as the status of permission is currently prompt, which means the PermissionRequested event will fire or the user will be prompted. Note: An exception to this is, if there is a parent directory handle that has broader permissions in the same page context than specified in here, the handle will automatically inherit the most permissive permission of the parent handle when posted to that page context. i.e. If there is already a FileSystemDirectoryHandle to C:\foo that has write permission on a page, even though a CoreWebView2FileSystemHandle to file C:\example\file.txt may be created with ReadOnly permission, when posted to that page, write permission will be automatically granted to the created handle. Additionally, the app must have the same OS permissions that have propagated to the WebView2 browser process for the path it wishes to give the web content to read/write the file. Specifically, the WebView2 browser process will run in same user, package identity, and app container of the app, but other means such as security context impersonations do not get propagated, so such permissions that the app has, will not be effective in WebView2.

Returns

CoreWebView2FileSystemHandle

Remarks

An app needs to be mindful that this object, when posted to the web content, provides it with unusual access to OS file system via the Web FileSystem API! The app should therefore only post objects for paths that it wants to allow access to the web content and it is not recommended that the web content "asks" for this path. The app should also check the source property of the target to ensure that it is sending to the web content of intended origin. Once the object is passed to web content, if the content is attempting a read, the file must be existing and available to read similar to a file chosen by open file picker, otherwise the read operation will throw a DOM exception. For write operations, the file does not need to exist as FileSystemFileHandle will behave as a file path chosen by save file picker and will create or overwrite the file, but the parent directory structure pointed by the file must exist and an existing file must be available to write and delete or the write operation will throw a DOM exception.